Technical Field
The present invention relates to a cryogenic refrigerator that generates cryogenic refrigeration using a high-pressure refrigerant gas supplied from a compression device, and a displacer used for the cryogenic refrigerator.
Description of the Related Art
Generally, a refrigerator (GM refrigerator) using a Gifford-McMahon cycle as a small-sized refrigerator for obtaining a cryogenic environment is known in the related art. In the GM refrigerator, supply and exhaust of a refrigerant gas (working fluid) compressed in a compressor are periodically performed by opening and closing of a valve.
In the GM refrigerator, a high-pressure refrigerant gas supplied from the compressor is first introduced into a room-temperature space (room-temperature chamber) provided on a high-temperature side within a cylinder, and is then introduced into an expansion space formed at a low-temperature end through a regenerator in the displacer from the room-temperature chamber. Then, cooling is generated as the refrigeration expands in the expansion space.